The bacterium, Campylobacter jejuni, is a major cause of diarrheal illness in both the developed and developing world. It is estimated that Campylobacter may affect as many as 400 million people and cause 14 percent of all diarrheal cases worldwide. There is currently no human vaccine for the prevention of Campylobacter disease or colonization. Live, attenuated Salmonella typhi is the most frequently studied vector for delivering foreign (vaccine) antigens in humans. More current thinking, however, suggests that attenuated vectors based on S. typhimurium may more effectively focus the induction of gastrointestinal immune responses to optimize against mucosal infection such as Campylobacter. Attenuated S. typhimurium vaccines elicit the production of immune responses in the intestinal tract inducing both systemic and mucosal immunity. Our goal is to construct live, attenuated strains of S. typhimurium that express C. jejuni genes that encode antigens known for their role in adherence, invasion or colonization, and to evaluate these strains for the capacity to induce systemic and mucosal immune responses that protect against Campylobacter infection. The accomplishment of these goals will provide new Campylobacter vaccines with the potential to rapidly confer protective immunity by oral immunization in humans.